The present invention relates generally to telephone equipment and more particularly to telephone entrance terminals and network interfaces usable to implement both multiple line telephone connections and single line telephone connections.
In compliance with present FCC regulations, telephone networks are designed so that they may be readily split between the telephone utility company side (the "facility side") and the telephone user side (the "Customer Provided Equipment side", "CPE side" or "user side"). In accordance with this practice, telephone networks are conventionally designed with a plug-type connector or network interface which serves as the line of demarcation between telephone utility company property and customer property. This line of demarcation serves to identify which party is responsible for installation and maintenance and also serves as a convenient point at which the telephone network can be temporarily severed so that one side of the network can be tested without affecting the other side.
Although practices vary, depending on particular local telephone company standards, particular customer's needs, and the vintage of the installation or subsequent modifications to it, a typical telephone network will usually include some form of entrance cable leading into the building, a lightning protector, and a terminal. A typical telephone entrance cable consists of 25 pairs of insulated conductors, although larger and smaller cables are also prevalent. Each pair of conductors comprises one transmission line or communication line. In this regard, it will be understood that two conductors are normally required to comprise a complete electrical circuit. According to industry practice, one of these conductors is referred to as the "ring" conductor or wire, while the other is referred to as the "tip" conductor or wire. In order to insure network-wide compatibility, particularly when implementing touch tone dialing or digital data transmission, it is necessary that the respective tip and ring polarities should not become crossed. In other words, the entire telephone network must be implemented so that between any two pieces of communication equipment (perhaps located hundreds of miles apart) the ring wire at one piece of equipment is electrically the same wire as at the other piece of equipment. The failure to follow this convention can, and often does, result in faulty performance of touch tone telephones and digital data communication equipment.
The building entrance terminal described above provides a termination point for the building entrance cable after it has passed through the lightning protector. The building entrance terminal also serves as a connection or junction between the telephone company facilities and one or more network interfaces. Commonly, building entrance terminals are produced in a number of different sizes to accommodate different numbers of conductor pairs, e.g. 12, 25, 50 and 100 pairs. It is often customary to place the building entrance terminal together with the ligtning protector in a main entrance room or terminal room within a building. Often this main entrance room is located on the ground floor, particularly in a multiple story building.
According to customary practice, the building entrance terminal feeds one or more network interface units, which in turn serve as the connection point or line of demarcation between telephone utility company equipment and customer provided equipment. In the case of multiple story buildings or buildings with a multiplicity of tenants, network interface units can be located throughout the building, using riser cables to reach the upper floors. If a riser cable is used, it is not uncommon to terminate the riser cable with a riser terminal, which in turn connects to one or more network interface units.
The particular equipment connected to the customer or user side depends essentially on the customer's needs. If the customer needs only a single line phone set (one telephone number) then a single line network interface unit such as the RJ11 network interface unit may be used. This network interface unit provides a modular jack to receive the miniature plug such as shown in U.S. Pat. No. 4,231,628. If the customer requires multiple extensions, then a multiple line network interface unit such as the RJ21 network interface unit has been traditionally used. The RJ21 network interface unit provides a readily attachable and detachable 25-pair connector to receive a mating connector supplied by the customer for connecting to the customer's key equipment, electronic switching equipment, switchboard, phone sets, and the like.
While the above describes one possible telephone network configuration, there are many variables and thus many other possible configurations.
If, for example, it is desired to implement only one multiple line telephone system within a building, then under present practice a separate multiple line network interface unit must be installed for connecting between the building entrance terminal and the customer provided equipment. If it is also desired to implement one or more separate single line telephone networks (as at some later date), then one or more additional single line network interface units must also be installed in order to connect between the building entrance terminal and the single line telephonic devices.
As a building's demand for multiple lines and single lines can vary over the years with changing tenants, the practice has heretofore been to install or remove additional multiple line and single line network interface units on an ad hoc basis according to the customer's needs. Such practice has tended to place various network interface units in scattered locations throughout a building. This increases installation costs and makes fault detection and trouble-shooting more difficult, time consuming and expensive. In addition to the inconveniences and expense caused by this ad hoc approach to telephone system installation, each of the above required items, the building entrance terminal, the multiple line network interface unit and the single line network interface unit, are generally bulky, comparatively complex and expensive.
The increasing popularity of customer installed telephones, answering machines, data communication equipment such as modems, facsimile transmission equipment and the like, has made it increasingly important that the telephone connection equipment be simplified. In this regard, modular equipment which will readily connect to miniature telephone line cord jacks is highly desirable. Consistent with the modular concept, there is also a need to miniaturize and consolidate telephone building entrance terminal equipment and network interface equipment, in order to lower system costs and installation and trouble-shooting costs.
The present invention accomplishes the above improvements in the telephone system by providing a combined terminal and network interface apparatus for providing both single line and multiple line connections to a telephone network. The invention thus replaces the separate building entrance terminal and network interface units with a single modularized unit, thereby reducing the overall system costs and simplifying installation and trouble-shooting.
In accordance with the invention, the combined terminal and network interface apparatus comprises a framework having a plurality of normally noncommunicating groups of associated signal conductors or contacts disposed thereon. A first means for establishing multiple connections is provided for connecting to a first part of the telephone network such as the incoming telephone cable or facility side, while a second means for establishing multiple connections is provided for coupling to a second part of the telephone network, such as customer provided equipment. A first one of the conductors of a given group of associated conductors is coupled to the first connection means, while a second one of the conductors of the given group is coupled to the second connection means. The associated signal conductors of a given group are normally open, but may be bridged using a bridge connector which attachably and detachably connects to the framework for providing signal communication between a given pair of conductors, when attached to the framework. When attached, the bridge connector provides signal communication between at least one line of the first and second connection means. By selectively attaching a purality of bridge connectors at selected locations on the framework, any one of a number of different possible multi-line connections can be established between the incoming telephone cable and the customer's multiple line system.
The invention further comprises at least one single line connector for attachably and detachably connecting to the framework, for providing signal communication between the single line connector and either the first or the second connection means. More specifically, the single line connector provides signal communication between a selected line or group of lines coming from the facility side telephone cable, in order to establish a single line telephone connection.
Also in accordance with the invention, a network interface apparatus is provided comprising a framework having a plurality of electrical contacts arranged in longitudinally spaced relation to one another and having a plurality of upwardly extending guideposts interdigitated with the contacts. At least one single line connector module is provided for attachably and detachably connecting to the framework. The connector module comprises a module body having a plug-receiving aperature in one face thereof, and a rigid extension structure extending laterally from the module body. The extension structure includes a receptacle for engagement with one of the guideposts and has at least one conductive member for electrical connection to a selected one of the plurality of electrical contacts. The extension structure, when engaged with one of the guideposts, supports the connector module in a fixed position relative to the framework, so that the plug-receiving aperature is substantially and laterally offset relative to the contacts.
Further in accordance with the invention is provided a combined terminal and network interface apparatus for connection to a telephone network providing signal conductors of first and second polarities. The invention comprises a framework having a first row of pairs of associated conductors and a second row of pairs of associated conductors. The first and second rows are arranged such that each of the pairs in the first row corresponds to a pair in the second row, and thereby defines a plurality of conductor groups of corresponding pairs. A means is provided for connecting the conductor groups to the telephone network signal conductors so that the polarity of any conductor group is opposite to that of the next adjacent conductor group. The apparatus may be used with the bridge connectors and single line connectors described above to implement a wide variety of different possible connections. The unique alternating polarity arrangement insures that the tip and ring lines will always be connected in the proper polarities. The invention is therefore fully compatible with touch tone dialing systems and digital data transmission equipment.
For a more complete understanding of the invention, its objects and advantages, reference may be had to the following description taken in conjunction with the accompanying drawings.